Bacteria are the second smallest living things on Earth with only viruses being smaller. They are very small organisms which usually consist of only a single cell. They do not have chlorophyll that is found in plants which allow for the production of food. If one million of the tiny bacteria were laid end-to-end, they would only measure about two inches. The word bacteria is plural, and bacterium describes a single organism.
An amateur scientist named Anton van Leeuwenhoek was the first person to see bacteria and other tiny organisms under a microscope. Though tiny, they are found everywhere. Bacteria is found in the air, soil, and water, as well as inside and outside of the human body. They reproduce quickly if the conditions are right. Millions of the tiny organisms can form in a space as small as a drop of water.
Bacteria are usually placed in three categories depending on their shapes. The can be described a spherical (like a football), rod-like, or shaped like a spiral or corkscrew. There are also some bacteria shaped like a comma used in writing, but much smaller. There is helpful bacteria and harmful bacteria. Some can improve human life, but others can cause diseases. In addition, there are many more that simply have no effect on humans.
The helpful bacteria assist with the digestion of foods in several kinds of animals including cows, deer, sheep and others. The bacteria help break down some of the foods the animals eat. In humans, a bacteria called E. coli also occur in the digestive system breaking down many kinds of foods. It is responsible for producing vitamin K and certain b vitamins.
Other bacteria are decomposers in the food chain, which attack dead animals and break them down. They are then used as nutrients by plants. Bacteria is also part of the production of many foods eaten by people. Bacteria causes milk to become sour which helps in the production of buttermilk, cottage cheese, and yogurt. Bacteria is involved in the production of sauerkraut and vinegar too.
Unfortunately, bacteria are best known by the disease it causes. It can directly attack the tissues in a plant or animal. Sometimes fruits or vegetables become discolored due the attack by bacteria. Bacteria can also cause harm organisms by releasing chemicals that are poisonous to plants and animals. One type is responsible for a disease known as tetanus, which can paralyze the muscles of a person. The condition when this occurs is called lockjaw. Finally, the worst type of food poisoning is caused by a bacterium releasing a toxin. This type of food poisoning is called botulism.
There are also harmful bacteria living on the skin, but are not dangerous unless they enter the bloodstream through a cut in the skin. If E. coli, though helpful with digestion, enters the bloodstream it can cause cramping, diarrhea and maybe even death.
Methods to destroy bacteria include freezing and drying during food preservation or through pasteurization, which is the process of heating food to a specific temperature for a period of time. This is how bacteria are killed during the processing of milk.
In summary, bacteria are everywhere and can be harmful or helpful to humans and other organisms.